Structural Properties of Lateral Collateral Ligament Reconstruction at the Fibular Head

Abstract

Background Anatomical reconstruction of a ruptured lateral collateral ligament using allograft tissue secured within the fibular head with an interference screw has been described. Hypothesis Interference fixation at the fibular head does not reproduce the strength of the intact ligament. Study Design Controlled laboratory study. Methods Ten intact lateral collateral ligaments were tested to failure. The distal fixation of 11 ligaments reconstructed with a graft including a bone plug and 11 ligaments reconstructed with a graft without a bone plug were also tested. Results The reconstructed ligaments consistently failed at the fibular head. The intact specimens predominately failed through ligament rupture. The mean strength and stiffness values were 460 ± 163 N and 82 ± 25 N/mm, respectively, for the intact ligaments, 113 ± 40 N and 36 ± 10 N/mm, respectively, for reconstruction with a bone plug, and 135 ± 81 N and 34 ± 14 N/mm, respectively, for reconstruction without a bone plug. The strength and stiffness were significantly (P <. 05) greater for the intact ligaments than for either reconstruction group. The variation in strength was significantly larger for reconstruction without a bone plug than for reconstruction with a bone plug. Conclusion Tension applied to lateral collateral ligaments reconstructed using fibular interference fixation should be limited immediately after surgery. Soft tissue fixation should be employed with care because of the inconsistency in the failure strength. Clinical Relevance Although fibular interference fixation is increasingly being described in the literature, the properties of reconstructed lateral collateral ligaments have not previously been quantified.